Melt spinnable polyamide dyed with stable anthraquinones



United States Patent ()fiice 3,291,771 Patented Dec. 13, 1966 Claims priority, application Switzerland, Feb. 23, 1961,

2.184/ 61 2 Claims. (Cl. 26037) The dyeing of linear polyamides in the melt requires dyestuifs having so high a stability that inorganic pigments have generally been used for this purpose. How ever, such pigments have a low coloring power. Moreover, the fibers colored therewith have rather dull tints. Attempts have therefore been made to use organic pigments Whenever possible, rather than inorganic pigments. However, only very few organic dyestuffs are known which are stable to polyamide melts. Even the usual anthraquinone vat-dyestuifs are useless for this purpose, because they are reduced by the polyamide melt.

The present invention is based on the unexpected observation that anthraquinone dyestuffs of the formula in which each A represents an anthraquinone radical, and B represents an at least bicyclic non-vattable aryl radical, are resistant to polyamide melts, and are espec i ally suitable for dyeing spinnable polyamides in the melt.

As spinnable polyamides there may be used in the process of the invention, polyamides such as are obtained, for example, from e-caprolactam (trade name Pei-Ion), w-amino-undecanic acid (trade name Rilsan), hexamethylene diamine and adipic acid (trade name nylon) or analogous starting materials. There may also be used mixed polyarnides, (for example, of e-caprolactam and hexamethylene diamine and adipic acid. The polyamides are advantageously used in a disintegrated form as socalled' chippings.

The dyestuffs of the Formula 1 contain at least one bicyclic aryl radical B, for example, a naphthalene, anthraccne, fluoranthene, pyrene or advantageously a crysene radical. As anthraquinone radicals A there may be mentioned, in addition to the simple anthraquinone radical and its substitution products, anthraquinone radicals which also contain fused-on carbocyclic or heterocyclic rings, such, for example, as the radicals of 1:2- benz-anthraquinone of anthraquinone-isothiazole-anthrone or of anthrapyrirnidine. Of special interest are dyestuifs of the formula in which B represents a naphthalene or chrysene radical, and one X in each anthraquinone radical represents an acylamino group and the other Xs represent hydrogen atoms. As acylamino groups there may be mentioned those of aliphatic monocarboxylic acids, for example, acetic acid, or of heterocyclic monocarboxylic acids, for example, pyridine monocarboxylic acid, and especially of aromatic monocarboxylic acids, for example, naphthalene monocarboxylic acids, and advantageously benzoic acid and substitution products thereof, for example, ortho-, metaor para-chloroor -methylor methoxy-benzoic acids. Such dyestuffs are known, and their manufacture is described, for example, in US. Patent No, 2,272,012 granted February 3, 1942 to Walter Kern et al. and in British Patent Nos. 498,602 and 522,657.

The polyamide to be dyed is bread-crumbed in the form of a powder, granules or chippings with the dry dyestuif powder, that is to say, the polyamide and dyestufr" powder are mixed together mechanically in such manner that the particles of the polyamide are coated with a layer of the dyestuff powder. The dyestutf is advantageously present in a finely divided form. Especially good restate in the form of chippings with '1 part of dyestutf of the formula CaHsCOHN O sults are obtained by using a dyestutf preparation consist- 5 I ing of a fine powder of the material to be dyed which contains the dyestuff uniformly dispersed therein. Such preparations can be obtained, for example, in the manner described in Belgian specification No. 567,953 by dispers- H ing a pigment in a solution of the polyamide in formic 0 EN acid and precipitating the pigmented polyasmide by the addition of water. 1 a

The bread-numbed polyamide particles are then melted and spun in known manner or otherwise shaped, for example, formed into sheets. The polyamides can also be dyed by adding the dyestufi before, during or at the end of the polycondensation of the monomer. The I; NHGOCGHS colored material so obtained is then shaped, in the same in a very fine state of division The bread crumbed,, a as g g i i or m admumue 2 chippings are spun in the usual manner, for example, by P; g d b h the grate spinning method, at about 290495 c. The 6 Po w as sen 6 Proc' filaments so obtained have a deep :brown tint, and the ass of the mventlQn, can be Worked l1P mm Special Struc' dyeing has an excellent fastness to light and excellent tures, more especially spun into fibers. The dyed fibers Properties f wet fasmess' so obtained are distinguished by their very attractive Instead f a polyamide obtained f hexamethylene brown tints of good brilliance and having excellent fastdi i d di i id, there may b d ith equal ness to light and excellent properties of wet fastness. success a polyamide obtained from e-caprolactam or The following examples illustrate the invention, the aminoundecanic acid. parts and percentages being by weight: Example 2 The procedure is the same as described in Example 1, Exa m pie 1 except that the dyestufit' used is replaced by one of the dyestufis given in column I of the following table. In this manner the polyamides. mentioned in that example 99 parts of a polyamide obtained from hexamethylene are dyed tints havingv excellent properties of fastness, the diamine and adipic acid are bread-crumbed in the dry tints of the dyeings being given in column IL.

No. I 11 1- yellow-brown.

II I I H H o O H E I I II N I N-o H t 0 2 red-brown.

I o N I H H I No, I II II I f u 3.... yellow-brown.

II EN (i HN H W 0 H H l O t l 4 yellow-brown.

II 0 H1? I II 0 CHaCOHIIT O 5 yellow-brown.

II I 0 EN II 0 NHGOGH The dyestuffs used in the foregoing examples can be obtained by the process described in the afore-mentioned patents, column 2, lines 53, by condensing the appropriate monoacylated diamino-anthraquinone with the apdescribed in Example 5 of British Patent No. 498,602 by condensation of 1 mol. of 1,4-dich1oro-naphthalene with 2 mols. of 1-amino-5-benzoylaminoanthraquinone and propriate dibromo-naphthalene or 2:8-dibromochrysene irarbazohzglg the so obtamed comgound' The dyestufi followed by carbazolization in sulfuric acid of 96% 4 of t e tab1e may be Prepared m an analogous Strength at ()to 5 c ner by starting from 1,5-d1ch1'om-naphthalene instead of I The compound No. 3 of the table may be prepared as 1,4-dich1oro-naphtha1ene.

and

in which one X in each anthraquinone radical represents acylamino and the other Xs represent hydrogen atoms.

2. A spinnable polyamide from hexamethylene diarnine and adipic acid having incorporated in finelydivided form the dyestuff of the formula OaH COHN References Cited by the Examiner UNITED STATES PATENTS Mieg et a1 260-316 1/ 1942 2/ 1942 Kern et a1 2603 16 3/ 1944 Graves. 10/1951 Water et a1. 10/ 1961 Altermatt et a1.

FOREIGN PATENTS 1/ 1939 Great Britain. 6/1940 Great Britain. 6/ 1960 Great Britain.

MORRIS LIEBMAN, Primary Examiner.

MILTON STERMAN, Examiner.

T. D. KERWIN, I.

w. BEHRINGER, A.

KOECKERT, Assistant Examiners. 

1. A SPINNABLE POLYAMIDE OF HEXAMETHYLENE DIAMINE AND ADIPIC ACID HAVING INCORPORATED IN FINELY DIVIDED FORM A DYESTUFF SELECTED FROM THE GROUP CONSISTING OF THE FORMULAE 